1. Field of the Invention
The present invention is in the field of optical devices and is directed more particularly to a specular microscope having a wide field scanning device intended particularly for the examination under magnification of a selected area within the relatively transparent cornea of the eye.
2. Prior Art
Recent studies have demonstrated the importance of being able accurately to inspect the cellular structure within the cornea of the eye of a subject. More particularly, the cornea is comprised of three transparent layers, namely the epithelium, stroma, and the endothelim. It has been determined that the cellular structure, particularly of the endothelium, is of particular significance in respect to performing corneal transplant operations since it is these cells which are responsible for maintaining corneal transparency. By careful examination of such layer, it is now possible to predict whether a particular donor cornea will result in a successful corneal transplant.
Furthermore, the ability to make a detailed inspection of the cellular structure of a wide area of the endothelial layer serves as an excellent diagnostic tool to determine various diseases of the eye for subsequent treatment.
In order for the physician to obtain an accurate indication of the endothelial cellular structure, it is necessary that a relatively wide area of the endothelial layer be inspected.
Where only a narrow region is able to be inspected, no spatial arrangement of the endothelial layer as a whole is possible, furthermore statistical analysis from multiple small fields is wrought with sampling errors.
Additionally, as noted since the cornea is comprised of a series of transparent layers, the image which may be derived utilizing conventional optical systems, is of extremely low contrast, since the observed image consists not only of light reflected from the surface sought to be examined, but also from light reflected or scattering from adjacent and intermediate reflective objects within the cornea.
Attempts have been made to devise optical apparatus which will enable corneal inspection of a relatively wide area. By way of example, reference is made to U.S. Pat. Nos. 3,547,512 of Dec. 15, 1970 and 4,170,398 of Oct. 9, 1979.
The devices of the subject patents while effective in a measure to permit corneal inspection of desired layers, comprise extremely complex optical and mechanical arrangements resulting in cumbersome and exceedingly expensive devices well beyond the financial capabilities of individual practioners and even of most medical institutions. Further by virtue of the complexity of the devices, it is mandatory that the same be operated by highly skilled technicians.